Portable terminal devices, for example, portable wireless telephone sets have been popularized by the development of mobile telephone systems in recent years. In portable wireless telephones sets, there is a type in which a first housing having a microphone part and a second housing having a speaker part are turnably connected via a hinge shaft, however, as such type of portable wireless telephone sets, some are designed so that the first housing and the second housing are turnably connected to the shaftwise direction of the hinge shaft, and the microphone part and the speaker part face to the same direction in a close state where the second housing is lying on the first housing (for example, see patent document 1).
As shown in FIGS. 38 and 39, in such a conventional portable wireless telephone set “a”, a first housing “c” having a microphone part “b” and a second housing “e” having a speaker part “d” are turnably connected via a hinge shaft “f”, and if the second housing “e” is turned to the first housing “c” from the close state where the second housing “e” is lying on the first housing “c” in the thickness direction (see FIG. 39), the portable wireless telephone set “a” becomes an open state (see FIG. 38) and becomes available for communication.
In the portable wireless telephone set “a”, a main operating part “g” having plural operation keys is provided on the surface of the first housing “c” on the side that touches the second housing “e”, and a display part “h” and a suboperating part “i” are provided on the opposite side. In this manner, in the portable wireless telephone set “a”, since the suboperating part “i” is provided on the surface on the opposite side of the second housing “e” to the side that touches the first housing “c”, the user can perform predetermined operations by operating the suboperating part “i” in both states of the open state and the close state.
On the other hand, as a further developed device from the said portable wireless telephone set “a”, there is an open/close type portable information terminal designed so that the angle of a housing having an operating part corresponding to the first housing “c” and a housing having a display part corresponding to the second housing “e” in the said open state becomes a predetermined angle θ; 180° or less (for example, see patent document 2).
patent document 1: patent application publication, publication number 07(1995)-288860
patent document 2: patent application publication, publication number 2002-158758 (p. 3, FIGS. 2 and 6)
However, in the said portable wireless telephone-set “a” (patent document 1), in the open state, it becomes the state where the first housing “c” and the second housing “e” are connected in almost straight and the shape is not along the outline of the caller's face when the caller performs communication; if the caller gets close to his/her mouth to the microphone part “b”, his/her ear gets away from the speaker part “d” (see FIG. 40), and reverse, if the caller gets close the ear to the speaker part “d”, the microphone part “b” gets away from the mouth (see FIG. 41): there is a problem that the usability is not good in both cases.
Then, to improve the usability, it can be considered that as a portable wireless telephone set a′ shown in FIGS. 42 and 43, a projecting part “j” is provided by making the part having the microphone part “b” in the first housing “c” project, however, since the projecting-part “j” is provided, the length of the first housing “c” becomes longer: it causes a problem that the portable wireless telephone set “a” becomes a large size.
Note that, this large size problem similarly arises also in the case where the part having the speaker part “d” in the second housing “e” is projected, without projecting the part having the microphone part “b” in the first housing “c”.
Furthermore, to improve the usability, as a portable wireless telephone set a″ shown in FIG. 44, it can be considered that the hinge shaft “f” is tilted to the first housing “c”, so that the second housing “e” tilts to the first housing “c”, however, in this case, since the second housing “e” is tilted, it is necessary that the hinge shaft “f” is longer, and a large gap generates between the first housing “c” and the second housing “e”: the hinge shaft “f” is apt to get a large load, and the whole of the portable wireless telephone set a″ becomes a large size.
On the other hand, in the said open/close type portable information terminal (patent document 2), the end part of the display part housing having the speaker and the end part of the operating part housing having the microphone are connected by a connecting member serving as a turning mechanism, and it is designed so that, in the state where the display part housing and the operating part housing are opened, they form a predetermined angle θ (180° or less), thereby, when the user performs communication, user's ear and mouth get close to the speaker and the microphone, respectively: the usability is improved.
However, although the open/close type portable information terminal is designed so that, in the state where the display part housing and the operating part housing are opened, they form a predetermined angle θ (180° or less), also there is a problem that if force is applied to the display part housing, the connecting member receives excessive load and is apt to be broken.